1. Field Of the Invention
The present invention relates to apparatus for securing a pad to a rotary floor machine of the type used in floor maintenance, and more particularly, a locking coupler for securing a pad to a rotating driver disc of a floor maintenance machine.
2. Description of Related Art
Coupler devices are well known for centering and coupling a floor maintenance pad to a pad driver disc. The pad driver disc is rotated by the drive shaft of a power-driven floor maintenance machine. One example of such a coupling device is illustrated and described in U.S. Pat. No. 4,536,912. Pad coupler devices typically have two parts which have mating threads. The first part is fixed to the driver disc and the second part is threaded to the first part to hold the pad in a centered position on the disc. The second part may be readily uncoupled by unthreading to replace the pad. The pads are replaced frequently due to wear or to use a pad with different abrasive characteristics.
Couplers are usually provided with either left-handed or fight-handed threads depending on the direction of rotation of the pad driver disc. The thread direction is chosen such that the theoretical resultant torque on the coupler tends to tighten the threaded connection. That is, a machine, which rotates counterclockwise as viewed facing the working surface of the pad, is provided with a coupler having a right-handed thread causing the coupler, in theory, to self-tighten during operation.
Despite the self-tightening design, couplers sometimes loosen during floor maintenance operations. The cause of the loosening is unknown, but is thought to be due to vibrations. Thus, there is a need for a coupler which holds and centers the pad, is readily uncoupled for changing pads, and which does not loosen during use.